This invention relates, in general, to high frequency semiconductor devices, and more particularly to a method for making a semiconductor device having an improved frequency response.
With the advent of the communications age, the number of electronic communications products available for consumers in the private sector has proliferated immensely. For example, the mobile phone market accounts for a significant portion of the sales and profits realized by many segments of the electronics industry today. Unfortunately, the increase in communications products has meant a reduction in the number of available radio frequencies to carry communications signals. Hence, manufacturers of electronic communications equipment have sought ways to solve this dilemma.
The approach several communications equipment manufacturers have taken is to design their products to operate at higher frequencies. Thus, the manufacturers of semiconductor components used in communications equipment must follow suit and design semiconductor devices to accommodate these higher frequencies. In the present state of the art, integrated circuit manufacturers have two semiconducting materials available that are capable of operating at higher frequencies: gallium arsenide and silicon. Although, gallium arsenide can readily handle higher frequencies, the cost is prohibitive for most applications. Silicon, on the other hand is relatively inexpensive, however several parasitic components inherent in silicon semiconductor devices surface under high frequency operation; the most insidious of which are the multitude of parasitic capacitances which arise. Accordingly, it would be beneficial to have a method for increasing the high frequency performance of semiconductor devices fabricated in silicon in order to take advantage of the lower cost associated with silicon.